Ye Olde Inn

Here is an idea for your heroes' quest rewards. I based it off of the Adventure Design Kit recommendation of 100-200 gold coins. In the first 14 quests, 200 is the most frequent amount, but there are a few in the range of 250-300, so I made 300 the upper limit. However, the later quest packs (elf, barbarian, etc) get pretty generous with the rewards, so the table below may be better suited to the earlier stages of a character's adventuring career.

Quest Reward Table
D20 gold coins
• 1. 110
• 2. 120
• 3. 130
• 4. 140
• 5 . 150
• 6. 160
• 7. 170
• 8. 180
• 9. . 190
• 10. 200
• 11 . 210
• 12. 220
• 13. 230
• 14. 240
• 15. 250
• 16. 260
• 17. 270
• 18. 280
• 19. 290
• 20 300

Then in the 1st EU edition you got a 500 gold bonus for surviving 3 quests. Huge bonuses for completing some quest packs too.

If you get too generous with the rewards the heroes may max out their gear too fast, or maybe they won't care as much about treasure searching if they know a big bonus is coming. Then again at a certain point mercenaries and potions can suck up their extra gold. I once toyed with the idea of the heroes having a regular "income" (like monopoly), perhaps the Emperor pays them 200 gold each mission in his service, but then I thought they are spending money in the background on their room & board, upkeep on their gear, medical bills, taxes, etc that we never see, so it's easier to just have the gold be pure profit that they find or get for completing their missions. If there's no bonus then some other benefit for the mission is good, but sometimes it's just doing what's right and stopping evil from overrunning the world. Whatever works for your setup! Harder quests having bigger benefits than easier ones seems logical enough.